<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>hello-big</title>
    <script src="./js/vue.js"></script>
</head>
<body>
    <div id="app" v-cloak>
        <input type="text" value="mystr" v-model="mystr" />
        <div id="mystr">{{mystr}}</div>
        <button @click="changeBig">变大</button>
    </div>
    <script>
        var app = new Vue({
            el:"#app",
            data:{
                mystr:"hello"
            },
            methods:{
            changeBig(){
                this.mystr = this.mystr.toUpperCase();
            } 
            }
        })
    </script>
</body>
</html>